Various remote control systems for motor vehicles are known and are widely used, especially in the area of security. Remote control keyless entry systems are typically a pocket-sized fob with one or more pushbuttons that send encoded RF signals to a vehicle-installed receiver and perform various functions such as locking and unlocking doors, locking and unlocking the trunk, activating and de-activating an alarm, turning lights on and off, and even starting the vehicle.
The key fob can be used within a fixed vicinity of the vehicle. The fob has a typical range of 10-20 meters from the vehicle. Special antennas and receivers can extend this to a practical limit of about 250-350 meters. Therefore, when a user is further away than typically 10-20 meters, the fob is ineffective.
Current systems that are capable of long range communications require software, hardware and special wiring changes to be made to the vehicle in order for the addition of the long-range system to be recognized by the vehicle. Because the addition of the long-range system is not transparent to the vehicle's existing short-range system, it adds unwanted cost and complexity to the remote control system. For high end luxury vehicle features, it is more cost effective to have one common high volume design that can be easily connected to numerous low volume unique vehicle architectures.
Thus there is a need for a long-range remote control system that does not add unwanted cost and complexity to a remote control system. In addition, the system should be capable of being retro-fit to later model vehicles that were originally produced without remote control, or keyless entry, systems without the need for extensive modifications to the vehicle and its wiring system.